const crypto = require('crypto');
const keyLen = 16

/**
 * @util 加密、解密工具类
 */
class CryptoUtil {

    /**
     * 解密
     * @param dataStr {string}
     */
    static Decrypt(dataStr, key, iv) {
        let cipherChunks = [];
        let decipher = crypto.createDecipheriv('aes-128-cbc', key, iv);
        decipher.setAutoPadding(true);
        cipherChunks.push(decipher.update(dataStr, 'base64', 'utf8'));
        cipherChunks.push(decipher.final('utf8'));
        return cipherChunks.join('');
    }

    /**
     * 加密
     * @param dataStr {string}
     */
    static Encrypt(dataStr, key, iv) {
        let cipherChunks = [];
        let cipher = crypto.createCipheriv('aes-128-cbc', key, iv);
        cipher.setAutoPadding(true);
        cipherChunks.push(cipher.update(dataStr, 'utf8', 'base64'));
        cipherChunks.push(cipher.final('base64'));
        return cipherChunks.join('');
    }
    // 随机数生成
    static RandomNum() {
        let num = '';
        for (let i = 0; i < keyLen; i++) {
            num += Math.floor(Math.random() * 10)
        }
        return num;
    }
}

module.exports = CryptoUtil;
